modules/client/rooms: Implement Client (unstable) rooms/relations. (Closes #126)

modules/Makefile.am

@@ -273,6 +273,7 @@ client_client_rooms_la_SOURCES = \
 	client/rooms/read_markers.cc \
 	client/rooms/initialsync.cc \
 	client/rooms/report.cc \
+	client/rooms/relations.cc \
 	client/rooms/rooms.cc \
 	###
 

modules/client/rooms/relations.cc

@@ -0,0 +1,155 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+#include "rooms.h"
+
+using namespace ircd;
+
+resource::response
+get__relations(client &client,
+               const resource::request &request,
+               const m::room::id &room_id)
+{
+	if(!m::exists(room_id))
+		throw m::NOT_FOUND
+		{
+			"Cannot take a report about %s which is not found.",
+			string_view{room_id}
+		};
+
+	if(request.parv.size() < 3)
+		throw m::NEED_MORE_PARAMS
+		{
+			"event_id path parameter required"
+		};
+
+	m::event::id::buf event_id
+	{
+		url::decode(event_id, request.parv[2])
+	};
+
+	if(!m::exists(event_id))
+		throw m::NOT_FOUND
+		{
+			"Cannot get relations about %s which is not found.",
+			string_view{event_id}
+		};
+
+	if(request.parv.size() < 4)
+		throw m::NEED_MORE_PARAMS
+		{
+			"relation first path parameter required"
+		};
+
+	if(request.parv.size() < 5)
+		throw m::NEED_MORE_PARAMS
+		{
+			"relation second path parameter required"
+		};
+
+	char rbuf[2][256];
+	const string_view r[2]
+	{
+		url::decode(rbuf[0], request.parv[3]),
+		url::decode(rbuf[1], request.parv[4]),
+	};
+
+	const unique_buffer<mutable_buffer> buf
+	{
+		96_KiB
+	};
+
+	json::stack out{buf};
+	json::stack::object top
+	{
+		out
+	};
+
+	m::event::idx next_idx
+	{
+		index(event_id, std::nothrow)
+	};
+
+	json::stack::array chunk
+	{
+		top, "chunk"
+	};
+
+	const m::event::fetch event
+	{
+		next_idx, std::nothrow
+	};
+
+	if(event.valid)
+		chunk.append(event);
+
+	const auto each_ref{[&r, &next_idx, &chunk]
+	(const m::event::idx &event_idx, const m::dbs::ref &)
+	{
+		const m::event::fetch event
+		{
+			event_idx, std::nothrow
+		};
+
+		if(!event.valid)
+			return true;
+
+		const json::object &m_relates_to
+		{
+			json::get<"content"_>(event).get("m.relates_to")
+		};
+
+		const json::string &rel_type
+		{
+			m_relates_to.get("rel_type")
+		};
+
+		if(rel_type != r[0])
+			return true;
+
+		chunk.append(event);
+		next_idx = event_idx;
+		return false;
+	}};
+
+	while(next_idx) try
+	{
+		const m::event::refs refs
+		{
+			next_idx
+		};
+
+		if(refs.for_each(m::dbs::ref::M_RELATES, each_ref))
+			break;
+	}
+	catch(const std::exception &e)
+	{
+		log::error
+		{
+			m::log, "relation trace from %s on %ld :%s",
+			string_view{event_id},
+			next_idx,
+			e.what()
+		};
+
+		break;
+	}
+
+	chunk.~array();
+	top.~object();
+
+	return resource::response
+	{
+		client, json::object
+		{
+			out.completed()
+		}
+	};
+}

modules/client/rooms/rooms.cc

@@ -29,6 +29,16 @@ rooms_resource
 	}
 };
 
+resource
+rooms_resource_unstable
+{
+	"/_matrix/client/unstable/rooms/",
+	{
+		"(10.0) Rooms (unstable)",
+		resource::DIRECTORY,
+	}
+};
+
 resource::response
 get_rooms(client &client,
           const resource::request &request)
@@ -70,6 +80,9 @@ get_rooms(client &client,
 	if(cmd == "initialSync")
 		return get__initialsync(client, request, room_id);
 
+	if(cmd == "relations")
+		return get__relations(client, request, room_id);
+
 	throw m::NOT_FOUND
 	{
 		"/rooms command not found"
@@ -82,6 +95,12 @@ method_get
 	rooms_resource, "GET", get_rooms
 };
 
+resource::method
+method_get_unstable
+{
+	rooms_resource_unstable, "GET", get_rooms
+};
+
 resource::response
 put_rooms(client &client,
           const resource::request &request)

modules/client/rooms/rooms.h

@@ -214,3 +214,13 @@ ircd::resource::response
 post__report(ircd::client &,
              const ircd::resource::request &,
              const ircd::m::room::id &);
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// relations.cc
+//
+
+ircd::resource::response
+get__relations(ircd::client &,
+               const ircd::resource::request &,
+               const ircd::m::room::id &);